Silver halide color photographic material containing couplers substituted with dicyclopentyl phenoxy groups

ABSTRACT

A colorphotographic material with at least one silver halide emulsion layer which contains in dispersed form a color coupler substituted with a dicyclopentyl phenoxy group. This substitution lowers the melting point of the coupler and increases its solubility in solvents used to incorporate the couplers in photographic layers. Layers with these couplers are accordingly more stable.

United States Patent 1 Pelz et al. 1' Nov. 6, 1973 1 SILVER HALIDE COLOR PHOTOGRAPHIC [51] lnt. Cl G03c 1/40 MATERIAL CONTAINING COUPLERS [58] Field of Search 96/100, 56.5, 55 SUBSTITUTED WITH DICYCLOPENTYL PHENOXY GROUPS [56] References Cited [75} inventors: Willibald Pelz, Cologne-Dellbruck; UNITED STATES PATENTS Hans-Heinrich Cr dn 2,920,961 1/1960 Bush et al. 96/100 Hohenschaftlarn; Walter Schulte, 3,255,012 6/1966 Glockner et al. 96/100 Opladen; Alfons Klein, Dusseldorf; 3,558,700 1/1971 Kimura et al. 96/100 Karlfried Wedemeyer; Fritz Nittel, both of Cologne-Stammheim, all of Germany Assignee: Agfa-Gevaert Aktiengesellschaft,

Leverkusen, Germany Filed: Aug. 4, 1971 US. Cl 96/100, 96/9, 96/55, 96/562, 96/565 Primary Examiner-J. Travis Brown Att0rneyArthur G. Connolly et al.

[57] ABSTRACT A colorphotographic material with at least one silver halide emulsion layer which contains in dispersed form a color coupler substituted .with a dicyclopentyl phev noxy group. This substitution lowers the melting point of the coupler and increases its solubility in solvents used to incorporate the couplers in photographic layers. Layers with these couplers are accordingly more stable.

5 Claims, No Drawings The invention relates to color photography, and particularly to a photographic material with at least one silver halide emulsion layer, which material contains couplers in dispersed form.

The formation of color photographic images by coupling the development product of primary aromatic amino developing agents, so-called color forming developers, with color couplers is well known. The color couplers as well as the image dyes produced upon color forming development have to meet for practical purposes a number of conditions. The color couplers as well as the dyes must be stable against light and higher temperature and humidity. This is true for unexposed as well as processed photographic material. For example, an inadequate stability of the residual color coupler, which has not been reacted with the oxidation product of the color forming developer, often causes yellowing of the white parts of the processed image. The coupling reaction between the oxidation product of the color forming developer and the'color coupler must be sufficiently fast. The color couplers must be fast to diffusion and should yield a dye grain as small as possible upon color forming development. Moreover, the mechanical properties of the layers must not be deleteriously affected by the color coupler. Last but not least the color couplers should produce image dyes which absorb only in the desired range of the visible spectrum if possible without any undesired side absorption.

The couplers used to produce these dyes generally contain color-forming groups of the phenol or a-naphthol series for the production of the cyan partial image, of the pyrazolone-S or indazolone series for the production of the magenta partial image and derivatives of B-ketocarboxylic acids for example of the benzoyl acetamide series for the production of the yellow partial image. Suitable color couplers are described, for example, in US Pat. Nos. 2,423,730, 2,474,293 or 2,908,573. These color couplers are incorporated into the photographic layer in form of a finely distributed solution of the coupler in an organic solvent. Although many of these color couplers are satisfactory with respect to the absorption properties of the dye formed upon color forming development, they are of limited utility. Due to the high melting point and the unsatisfactory solubility of the couplers in organic solvents, a high solvent-tocoupler ratio must be applied. This, however, is disadvantageous because the inert material has no photographic function and because it tends to detract from the mechanical properties of the photographic layers. If the solvent-to-coupler ratio is lowered and a supersaturated solution is applied, very often recrystallisation occurs with this dispersion.

It is among the objects of the present invention to provide color couplers with a melting point as low as possible and a high solubility in organic solvents. Another object is to provide photographic materials with at least one silver halide emulsion layer, which material contains such a color coupler.

We have now found a light-sensitive colorphotographic iridium, with at least one silver halide emulsion layer, which material contains a color coupler capable of reacting with the oxidation product of a colorforming photographic developer upon development to form a dye, wherein said color coupler contains in a noncoupling position a dicyclopentylphenoxy group.

More particularly the color couplers of the present invention are characterized by the following formula:

K is a color coupler structure in particular a color coupler structure of the phenol, a-naphthoL- pyrazolone-S, or indazolone structure or an openchained aliphatic ketomethylene group, more particularly a coupler of the benzoyl acetanilide class; V is a bridging member through which the dicyclopentylphenoxy group is attached to the color coupler structure in a non-coupling position, par- R is hydrogen or a lower alkyl group having up to 5 carbon atoms particularly methyl; R is hydrogen or a straight-chain or branched alkyl group having up to 12 carbon atoms or phenyl, and

CHa

CHa

H 1 EN m l m a. NI H .1 1 O C m m O 5 O 3 4 4 5 A color coupler of the present invention is prepared ac- Cl cording to known methods starting from a dicyclopen-- tylphenol which is substituted as desired. The dicyclopentylphenols are prepared according to known methods by reacting the phenol with cyclopentene in the presence of acidic-catalysts.

The preparation of some couplers are described below in detail. Other couplers of the present invention are prepared in analogous manner. 4,6-dicyclopentyl-3-methyl-phenol Into an autoclave containing 1.296 kg (12 mols) of m-cres0l and g of activated bleaching earth (e.g. the product K 10 SF marketed by the firm Sudchemie AG) are pressed at 140C within 7 hours 1.716 kg (24 mols) cyclopentene (purity 95 percent). After 4 hours (pressure about 1.3 atmospheres gauge) the addition of cyclopentene is interrupted for minutes. After this time the inert hydrocarbons formed upon reaction of cyclopentene and the phenol are eliminated. After addition of the cyclopentene is completed the contents of the autoclave are stirred for-2 hours at 140C., then cooled to a temperature of 60-70C .and about 300 ml of toluene are added. Thereafter the catalyst is suctionfiltered off. Yield after evaporation of the solvent 2.67 kg.

The raw product is purified by distillation. 2.62 kg of 4,6-dicyclopentyl-3-methylphenol are obtained.

(Touplcr l 2,5-dicyclopentyl-4-methylphenoxybutyronitril 97.6 g of 2,5-dicyclopentyl-p-cresol (0.4 mol) are added to a solution of 9.2 g sodium (0.4 mol) in 240 mls of water-free ethyl alcohol. After 15 minutes 41.5 y-chlorobutyronitril (0.4 mol) dissolved in 50 ml alcohol are added and the mixture refluxed for 6 hours. The sodium chloride formed upon the above reaction is suction-filtered off. The nitril crystallizes from the filtrate, is suction-filtered and recrystallized from 400 ml alcohol. Melting point 74C; Yield: 62 g 2,5-dicyclopentyl-4-methylphenoxybutylamine 62 g of the above nitril are dissolved in 1 l alchohol and hydrogenated at 120C and 100 atmospheres in the presence of Raneynickel. After the reaction is completed the alcohol is evaporated and the residue purified by fractional distillation. The main fraction boils at 180 190C at 0.2 mmHg. Yield: g.

l-hydroxy-2 [delta-( 2 5 -dic yclopentyl-4'-methylphenoxy)-n-butyl]- naphthamide 40 g of the above amine are reacted with 31.6 of 1- hydroxy-naphthoicacid-2-phenylester at 140C in vacuo. The reaction mixture is precipitated from benzene and the precipitate recrystallized from alcohol. Melting point 105C.

Coupler 3 a-(2,5 dicycloperttyl-4-methyl-phenoxy)-n-caprylic acid ethyl-ester H g v 150 ml of xylene, 6 g of potassium hydroxide and 24.5 g of dicyclopentyl-p-cresol are heated in a 3- necked flask equipped with a dropping funnel, a reflux condenser, a stirrer and a device for separation of water. Further 150 ml of xylene are added during the reaction while water is eliminated from the separation device. 26.1 g of a-bromo caprylic. acid ethyl ester are added dropwise. After refluxing for 2 hours the precipitated sodium bromide is filtered off. Xylene is evapo rated and the residue'purified by fractional destillation at a pressure of 0.6 Torr. The main fraction boils at 180 200C; Yield: 27 g. a-(2,5-dicyclopentyl-4-methylphenoxy)-n-caprylic acid 27 g of the above ester dissolved in 300 ml of methanol are refluxed while adding 30 ml of'a 30 percent aqueous solution of sodium hydroxide. After addition of the sodium hydroxide solution it is refluxed for further 25 minutes. The reaction mixture is poured into 300 ml of water and 100 ml of hydrochloric acid and the reaction product extracted by shaking with methylene chloride. After evaporation of methylene chloride 20 g of the above acid are obtained. 1 a-(2,5-dicyclopentyl-4-methylphenoxy)-n caprylic acid chloride 20 g of the above acid are heated for 3 hours at C with 20 ml of thionyl chloride. Thereafter it is heated for 2 hours at C in vacuo to eliminate the excess of thionyl chloride. Yield 19 g.

2-( a-2',5 -dicyclopentyl-4-methylphenoxy-ncaprylamino)-4,6-dichlor-5-methylphenyl 200 ml of acetone, 12 g of 2-amino-4,6-dichloro-'5- methyl-phenyl hydrochloride (the preparation of this compound is described in German Pat. specification No. 1,003,586) and 10.5 g of dimethyl aniline are stirred for 15 minutes at room temperature. Thereafter 19 g of the abovecaprylic acid chloride are added, stirred for 1 hour and left standing overnight.

The solution is stirred with 500 ml of benzene (boiling range 50 75C) and the oily deposit separated. The benzene solution is washed twice with a mixture of methanol, water and hydrochloric acid, and water again. Thereafter the washed benzene solution is stirred with active carbon, filtered and evaporated. 20 g of coupler 3 crystallize, melting point 94C.

Coupler l 1 2-chloro-5-(a-2, 5 '-dicyclopentyl-4-methylphenoxypropionylamino aniline 64 g of oz-(2,5-dicyclopentyl-4-methyl-phenoxy)- propionic acid are refluxed for 3 hours with 70 ml of thionyl chloride. Thereafter the excess of thionyl chloride is distilled off. 92 g of the raw acid chloride are reacted in the presence of 25 g of sodium acetate and 25 ml water with a solution of 43 g of 4-chloro-3- nitraniline in ml of acetone. The reaction mixture is refluxed for 1 hour and poured into a mixture of 300 ml water (0C) and 50 ml of concentrated aqueous hydrochloric acid. The mixture is extracted with chloroform, the chloroform solution dried and the chloroform distilled off. The residue is recrystallized from aceto nitrile; melting point 124 125C.

The nitro compound thus formed is converted by catalytic reduction with Raney-nickel in methanol into the corresponding amine; melting point 79 82C. 4-methoxy-2 '-chloro-5 a-2 ,5 -dicyclopentyl-4- methylphenoxy-propionylamino)-benzoylacetanilide A mixture of 44g of the above amine, 27g of p-methoxybenzoylacetic acid ethyl ester and 150 ml of xylene are heated to a temperature of C. Alcohol formed by the resulting reaction is distilled off. After complete reaction the solvent is distilled off in vacu and the residue dissolved in methanol. The coupler crystallizes out and is recrystallized from methanol; melting point l1.4-118C.

Due to their unexpectedly low melting point and the high solubility of the color couplers of the present invention in the common solvents, such as acetic acid ester or methylene chloride, sufficiently stable solutions can be prepared. These solutions can'be easily incorporated into the photographic layers. No recrystallisation occurs, neither in the solutions nor in the photographic layers.

The couplers of the present invention are added in the form of their solution in photographic silver halide emulsion layers, or they can be added to nonlight sensi- The couplers of the present invention are added to I the photographic layers according to common practice. Since the couplers are hydrophobic compounds, they are dissolved in suitable organic solvents, such as esters of aliphatic carboxylic esters, in particular acetic acid ester or methylene chloride. These solutions are emulsified into the casting solution for the photographic layer. Since the couplers are excellently soluble it is in general not necessary to apply high-boiling solvents, the so-called oil-formers.

The couplers of the present invention show unexpectedly high coupling activity. This highly desirably properties can be fully utilized in the color photographic material since as referred to above no oilformer need be used for incorporating the coupler into the layer. Thus the coupler is not embedded in a hydrophobic phase (droplets of the oil-former) in the photographic layer.

Another advantage of the couplers of the present invention is that they yield in particular with hydrophilic color-forming developers of the p-phenylene diamine series, for example N-butyl-N-w-sulfobutyl-pphenylenediamine, upon color-forming development dyes with considerably improved stability against tropic conditions such as high temperature and humidity as compared with couplers which contain an open-chain alkyl group in the phenol part of the molecule instead of the cyclopentyl groups but which have otherwise the same structure. This is in particular true with photographic materials having a support of baryta-coated paper or polyolefine laminated paper.

Suitable light sensitive emulsions are emulsions of silver halides, such as silver chloride, silver bromide or mixtures thereof, optionally with a small silver iodide content of up to 10 mols percent, in one of the commonly used hydrophilic binders, such as protein, especially gelatin, polyvinyl alcohol, polyvinyl pyrrolidone, cellulose derivatives, such as carboxymethyl cellulose, or derivatives of alginic acid.

The emulsions may also be chemically sensitized, e.g., by adding compounds which contain sulfur, for example allylisothiocyanate, allylthiourea or sodium thiosulfate, at the stage of chemical ripening. Reducing agents, e.g., the tin compounds described in Belgian Pat. Nos. 493,464 or 568,687, or polyamines, such as diethylenetriamine or aminomethansulfinic acid derivatives, may also be added as chemical sensitizers, e.g. according to Belgian Pat. No. 547,323.

Noble metals, such as gold, platinum, palladium, irridium, ruthenium or rhodium, and noble metal compounds are also suitable for use as chemical sensitizers. This method of chemical sensitization has been described in the article by R. Koslowsky, Z. Wiss. Phot. 46, 65-72 (1951).

The emulsions may also be sensitized with polyalkylene oxide derivatives, e.g. with polyethylene oxide having a molecular weight of between 1,000 and 20,000, or with condensation products of alkylene oxides and aliphatic alcohols, glycols or cyclic dehydration products of hexitols with alkyl-substituted phenols, aliphatic carboxylic acids, aliphatic amines, aliphatic diamines or amides. The condensation products have a molecular weight of at least 700 and preferably more than 1,000. These sensitizers may, of course, be combined for the purpose of achieving special effects, as described in Belgian Pat. No. 537.278 and in British Pat. specification No. 727.982.

The emulsions which contain the color couplers of the present invention may additionally contain spectral sensitizers, e.g. the usual monomethine or polymethine dyes, such as basic or acid cyanines, hemicyanines, streptocyanines, merocyanines, oxonoles, hemioxonoles, styryl dyes, including also methine dyes which have three or more nuclei, for example rhodacyanines or neocyanines. sensitizers of this type have been described, for example, in the work by F.M. Hamer The Cyanine Dyes and Related Compounds (1964), Interscience Publishers John Wiley and Sons. i

The emulsions may contain the usual stabilizers, e.g., homopolar or salt-type compounds of mercury which have aromatic or heterocyclic rings, such as mercaptotriazoles, simple mercury salts, sulfonium mercury double salts and other mercury compounds. Azaindenes are also suitable stabilizers, especially tetraor pentaazaindenes and particularly those which are substituted with hydroxyl or amino groups. Compounds of this type have been described in the article by Birr, Z.Wiss.Phot. 47, 2-58, (1952). Other suitable stabilizers are inter alia heterocyclic mercapto compounds, e.g. phenylmercaptotetrazole, quaternary benzothiazole derivatives or benzotriazole.

The emulsions may be hardened in the usual manner, for example with formaldehyde or halosubstituted aldehydes which contain a carboxyl group, such as mucobromic acid, diketones, methanesulfonic acid esters or dialdehydes etc.

The usual color developers are used for producing the color partial image, e.g., compounds of the pphenylene diamine series containing at least one primary amino group, such as N,N-dimethyl-pphenylenediamine, N,N-diethyl-p-phenylene-diamine, monomethyl-p-phenylenediamine and N-butyl-Nqnsulfobutyl-p-phenylenediamine. Other suitable color developers have been described, for example, in J. Am. Chem. Soc, 73, 3100-3125 (1951).

Particularly useful are cyan color couplers of the present invention including a cyan color coupler structure of the phenol or a-naphthol series. These couplers can easily be combined with colored couplers containing a red azo dye structure such as described for example in German Offenlegungsschrift P 15 97 510 and P 19 44 441. With these coupler mixtures an excellent masking of the yellow and magenta side absorptions of the cyan dyes formed upon color-forming development is obtained.

Example 1 A solution of 20 g of coupler l in 60 ml of acetic acid ethyl ester is emulsified into 320 ml of a 10 percent aqueous solution of gelatin containing ll ml of a 10 percent aqueous solution of saponine.

350 ml of this emulsion is stirred into 1 kg of a silver bromide gelatin emulsion containing g of gelatin and 0.4 mols of silver in the form of silver bromide.

The resulting dispersion is stored for several weeks. No recrystallisation occurs. The following additives are mixed with the above silver halide gelatin emulsion:

ml ofa 5 percent aqueous alkaline solution of the red cyan coupler of the following formula 9 SOaNa O-NH (g N \N/ 0143 ieHa1 5 H N @SOzNa HOzNa 25 ml of a 1 percent methanolic solution of l 5 4-hydroxy-6-methyll,3,3a, 7-tetraozaindene, 30 ml of a 10 percent aqueous solution of saponine and ml of a 0.5 percent aqueous solution of chromium acetate.

The final emulsion is cast onto a support of cellulose triacetate. The dried layer has a thickness of 4.5 micron. The pH- value of the layer is 6.5 7.

The dried material is exposed in a sensitometer customarily employed in the art through a stepless grey test wedge and developed for 15 minutes in the following developer:

5 g 2-amino-5-(N-ethyl-N-B-methansulfonamidoethylamino) -toluene-sesquisulfatmonohydrat 5 ml benzyl alcohol 2.5 g of sodium hexametophosphate 1.85 g of sodium sulfite anhydrous 1.4 g of sodium bromide 0.5 mg of potassium iodide 12.5 g of sodium hydroxide 34.2 g of sodium tetraborate Water up to l l. The further processing includes subjecting the developed emulsion to the following baths.

Stop bath 17 ml of acetic acid 2.94 g of sodium acetate anhydrous Water up to l l.

Hardening bath 0.3 g of sodium hydroxide 0.5 g of sodium hexametaphosphate 9 g of sodium carbonate and 20 ml of a 37 percent aqueous solution of formaldehyde Water up to l l.

Bleaching bath Fixing bath 150 g of ammonium thiosulfate 10 g of sodium sulfite Water up to l 1.

Final bath 0.3 g of sodium tetrapropylene benzene sulfonate Water up to l l. The processing times in the bath were as follows:

Stop bath 4 minutes Hardening bath 4 minutes Rinsing 5 minutes Bleaching bath 6 minutes Rinsing 5 minutes Fixing bath 8 minutes Rinsing 10 minutes Final bath 30 seconds A cyan test wedge is obtained at the exposed areas while at the unexposed areas the red dye of the masking coupler is still present. The sensitometric measurements show that the cyan dye is excellently masked in the blue and greenregion of the spectrum.

Example 2 A photographic material is made as described in Example with the exception that the emulsion of coupler l is replaced by 300 ml of an emulsion of coupler 2 and the masking coupler of Example 1 is replaced by 150 ml of a 5 percent aqueous solution of the red masking coupler of the following formula:

OH OaNa.

I 0 Ha C "H31 7 N H N l NaCOO S O aNa v The dried material is processed as described in Example 1 Similar results are obtained.

Example 3 1 part by weight of the cyan coupler referred to below is dissolved in 3 parts by weight of acetic acid ethyl ester, and in a second sample 1 part of the same coupler is dissolved in a mixture of 2 parts by weight of acetic acid ethyl ester and 1 part by weight of an oil former. The solutions are separately emulsifiedinto different samples of 16 parts by weight of a 10 percent aqueous solution of gelatin. The acetic acid ethyl ester is evaporated in vacuo by means of a rotating evaporator. Each sample is divided into two portions and 300 ml of these portions are mixed with 1 kg of a photographic silver bromide gelatin emulsion containing g of gela- The individual samples are exposed to a step wedge and processed as described in Example l.

The following color couplers are compared:

1 OH csHut C H| t=Comparison coupler The following oil formers were used:

Di Dibutylphthalate Tri Tricresylphosphate The maximum densities of the samples measured behind red filter are shown in the following table:

immediate storage for the Coupler solvent coupling casting dispersion for IS h l acetic acid ester 1.6

Di 1 acetic acid ester 2.0 0.] ll acetic acid ester Di 1.7 1.6 ll acetic acid ester 1.4 1.3 II acetic acid ester Tri 1.7 1.6

It is readily apparent from the above table that the comparison coupler can only be used in combination with the additional oil-former. Without the oil former the dispersion is not stable after storing for 18 hours at 40C.

We claim:

1. In a light-sensitive color photographic material containing a silver halide emulsion layer and a cyan color coupler of the phenol or a-naphthol type, a magenta coupler of the pyrazolone-S or indazolone type or a yellow coupler of the benzoyl acetamide type, the improvement according to which the coupler is substituted with a dicyclopentyl phenoxy group in a noncoupling position.

2. The combination of claim 1 wherein. the dicyclopentyl phenoxy group is linked to the remainder of the color coupler through abridging member of the follow ing formula:

CH; -N11 cocH- o- &

wherein R is hydrogen or alkyl having up to 4 carbon atoms.

5. The combination of claim 4 wherein R represents a methyl group.

I R UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,77 ,455 Dated November 6, 19 18 Inventor(s) 31111 51 15 BQJZ 31; a!

It is certified that; error appears in the above-identified patent: and that said Letters Patent are hereby corrected as shown below:

Column 2, the right-hand side of the formula of coupler 1 should read as follows:

Column 2, the" right-hand side of the formula of coupler 2 should read es follows: I v

FORM F'O- USCOMM-DC scan-ps9 i .5. GbVERNMENT PRIN ING OFFICE IGI 0-356-334.

L UNITED STATES PATENT OFFICE Pogo 2 CERTIFICATE OF CORRECTION Patent No. 3,770,445 Datedm Inventor-( PelZ et 8.].

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, the. right-hand side of -tho formula. o1 coupler 4 should read as follows:

Signed and sealed this mm day of June 1971;.

(SEAL) .Attest:

EDWARD M.FIE'I'CHER,JR. v C. MARSHALL DANN v Attosting Officer Comiaaionor of Baton F ORM PO-1050' (10-69) 

2. The combination of claim 1 wherein the dicyclopentyl phenoxy group is linked to the remainder of the color coupler through a bridging member of the following formula: -NH-(CH2)n-or
 3. The combination of claim 2 wherein the layer is a light-sensitive silver halide gelatin emulsion, the color coupler is a cyan coupler of the phenol or Alpha -naphthol series, and is dispersed in the emulsion without an oil former.
 4. The combination of claim 2 wherein the color coupler has the following formula:
 5. The combination of claim 4 wherein R represents a methyl group. 